Support and electrical connection for grid cup in electron gun



July 23, 1968 YORNS ETAL 3,394,279

SUPPORT AND ELECTRICAL CONNECTION FOR GRID CUP IN ELECTRON GUN FiledMarch 23, 1967 INVENTORS EDWARD E.YORNS JAY H. JOHNSON BY Wm May ATTORNUnited States Patent 3,394,279 SUPPORT AND ELECTRICAL CONNECTION FORGRID CUP IN ELECTRON GUN Edward E. Yorns and Jay H. Johnson, Owensboro,Ky., assignors to Kentucky Electronics, Inc., Owensboro, Ky., acorporation of Delaware Filed Mar. 23, 1967, Ser. No. 625,529 2 Claims.(Cl. 313-82) ABSTRACT OF THE DISCLOSURE A cathode ray tube electrodestructure is disclosed, which comprises a cup-shaped electrode with aconnection tab extending from a rim to engage a lead in the glass stemof the cathode ray tube which usually is a round wire. The tab istypically shaped as a split cylinder, preferably affording a tight fitupon the stem for engaging a portion thereof to hold it firmly andmechanically in place. The stem and tab are welded as the variouselectrodes are aligned along the electron beam axis.

This invention relates to electrode structure and, more particularly, itrelates to structure for electrically connecting electronic circuits toan electrode disposed within a cathode ray tube.

Within a cathode ray tube it is customary to support electron guns onstem leads extending through a glass stem or base which closes the tubeenvelope at the end of a long neck in which the gun resides. These stemleads serve both the purpose of mechanically supporting the gun andelectrically connecting the various electrodes to external electroniccircuits. In tube operation there are thermionic heaters disposed closeto the stem which provides significant thermal stresses to mechanicaljoints, generally simple spot welds, between the stem leads and theelectrodes.

Conventionally, various schemes of interconnecting the stem leads withthe electrodes have been used, and for this purpose a tab is generallywelded to the electrode for disposing adjacent to and spot welding tothe stem wire. This causes a series of several welds in the electricalconnections which can cause excessive resistance if the welding isfaulty, and may furthermore cause a disengagement of the spot weldsbecause of thermal and mechanical stresses. In addition, the spot weldsare generally manually done so that uniformity may not be good in eitherthe placement of the weld for best electrical or mechanical operation.For these reasons conventional electrode assemblies are expensive tomake, result in occasional rejects, and give a risk of failure duringoperation.

It is therefore an object of the present invention to provide improvedelectrode structures in cathode ray tubes.

A more specific object of the invention is to produce better mechanicaland electrical connections between the electrodes and the stern assemblyof a cathode ray tube.

Another object of the invention is to produce electrode structure for anelectron gun which requires fewer welding operations.

Accordingly, the present invention provides a cylindrical electrodewithin an electron gun that has an integral connection tab extendingtherefrom which is welded to the glass stem lead to support the electrongun assembly and make electrical connections therewith. Preferably, theintegral connecting tab has a clamping structure such as a splitcylindrical sheath for elastically encompassing a portion of the sternlead in good mechanical contact, and which may be welded in place tofirmly establish a permanent gun positioning.

3,394,279 Patented July 23, 1968 The foregoing features and objects aresupplemented in the more detailed description of the invention asillustrated by the specific embodiments referred to in the accompanyingdrawings, in which:

FIGURE 1 is a fragmentary view in perspective of an electron gunincorporating the invention,

FIGURE 2 is a plan view of an electrode constructed in accordance withthis invention, and

FIGURE 3 is an elevation view of a further embodiment of the invention.

As seen in FIGURE 1, an electron gun 5 is generally mounted upon theglass stem or base 6 by means of mechanical coupling between at leastthe first grid electrode 7 and the stem lead 8. The electron gun 5 has aseries of other electrodes 9, 10, etc. mechanically aligned by means ofbrackets 11 extending into a glass head 12 for a unitary electron gunassembly sitting upon several of the stern leads such as 8.

The first grid electrode 7, which is a generally cylindrical cup-shapedelectrode having an aperture 15 for passing an electron beam along axis16, is constructed by this invention to have extending from its rolledover external rim 17 a connection tab 18. In this embodiment the tab isformed to extend parallel to the axis 16 up alongside the body of thefirst grid electrode 7. It is further shaped to provide a generallysplit cylinder clamp structure 20 for receiving and holding the roundwire stem 8 with a firm mechanical coupling. For this purpose,preferably the inside diameter of the split cylinder 20 is slightly lessthan the diameter of the stem wire 8.

The tab extension clamp 20 is spot welded to the stem lead 8 at one ormore points 22 depending upon optimum electrical and mechanicalrequirements. The stem 8 may be bent or shaped to fit the position ofthe grid 7 as desired, and in the case of a three gun color tube, atleast three firm first grid mounting positions are provided to producesubstantial support for holding the gun in mechanical alignment.

As may be seen from the plan view of grid electrode 7' in FIGURE 2, thetab 18' extends radially from rim 17. Preferably it is formed withclamping structure such as shown in FIGURE 1 which permits the gun toslip onto stem leads disposed generally axially alongside the electrodebody. However, other structures: may be desirable such as that shown inFIGURE 3, where the stem 8' is bent normally to engage the rolled overtab 25 which provides an alternative form of the generally splitcylinder clamp to extend generally normally from the axis 16 of theelectron beam.

The tabs may be either preformed in substantially final form, or theymay be partially formed for final shaping during the welding operationif desired. In this case, the electrode structure would be either agenerally fiat tab or would be partially formed to loosely enclose orclamp the stem lead. In general, a single welding operation is all thatis required, since no tab need be welded on the electrode structure.

It is evident that some variations may be made from the embodimentsshown which do not depart from the spirit or the scope of the inventionwhich is represented in the appended claims.

What is claimed is:

1. A grid cup electrode assembly for the electron gun of a cathode raytube comprising in combination, a generally cylindrical single piececup-shaped electrode with an axial aperture for passing an electronbeam, a rim extending externally about the open mouth of said cup-shapedelectrode, a mounting bracket affixed to said electrode for positioningand holding it in an electron gun assembly, said cup-shaped electrodebeing the first grid 3 in said electron gun assembly, an integral leadconnecting tab extending from the rim of said cup-shaped electrode andhaving a longitudinal portion in the form of a slitted cylinder disposedaxially in a direction parallel to said electron beam, a glass stemhaving at least one conductive lead extending therethrough, said leadbeing a circular Wire Whose end remote from said stem is enclosed withinand secured to said slitted cylinder by a single conductive connection.

2. An assembly as defined in claim 1, wherein the shaped structure isdisposed alongside the exterior of said electrode.

References Cited UNITED STATES PATENTS ROBERT SEGAL, Primary Examiner.

